Prior to the 1950s farmers of orchard crops in California had plenty of new land available as an alternative to replanting land that had previously been in production. However, with growing population and increased land values, a greater proportion of fruit and nut production has been on land where older orchards have been removed. Farmers frequently encounter growth problems when they replant. In severe situations, new plants die. Plant parasitic nematodes that are present on old roots are a common cause of the replant problem.
“Orchard removal and site preparation for walnuts can be extensive and expensive, but worth the time and expense to get new plantings off to the best start, according to Joe Connell, University of California Cooperative Extension farm advisor for Butte County.
Nematodes are a main concern, and the first thing that a grower should do is collect a soil sample from the feeder roots in the old orchard and have a nematode analysis done, Connell said.
After the soil testing, the next step is to cut down the trees, and then treat the stump with a herbicide, Connell said. Treating the stumps kills the entire root system, and it will kill out the nematode population that is attached to that root system, he added.”
Author: Coatney, K.
Title: Walnut site preparation is essential for healthy orchards.
Source: Ag Alert. January 30, 2013.